OBJECTIVES: 1. To determine the effect of high concentrations of nucleotides, nucleotides, purines and pyrimidines in preventing the interference observed in cells infected with high multiplicities of infection of Colorado tick fever virus. Variations in the concentrations of the metabolites, time of addition of metabolites with respect to postinfection time and the host cell system used to cultivate the virus will be determine. 2. to demonstrate by ferritin-labeled antibodies the location and ultrastructure of cytomegalovirus induced Fc receptor sites, immediate early antigens and early antigens. The indirect ferritin-labeled antibody technic will be applied to thin sections of cytomegalovirus infected cells. Sections will be etched with hydrogen peroxide to expose antigenic sites which could then combine with various normal and immune area. 3. To determine by immune electron microscopy the antigenic relationship between varicella-zoster (VZ) virus and the dense bodies induced by V-Z virus. Density gradient purified V-Z virus and dense bodies will be incubated with monkey anti-V-Z virus serum and examined after negative staining.